Closure

ABSTRACT

A crown closure having a curled lower edge is described. The curled crown is typically formed from double reduced steel which is 35% thinner gauge than that used for conventional fluted crowns. The crown is also described in combination with a standard glass bottle. The curl of the crown tucks under the capping bead of the bottle so as to achieve standard pressure requirements. Added benefits of this configuration are not only the concealment of the edge of the closure but also the distinctive appearance of the product.

[0001] This invention relates to a crown closure and, in particular to acrown closure for use in the capping of bottles and the combination of acrown closure with a bottle having an outwardly extending capping bead.

[0002] Crown closures (hereinafter alternatively referred to simply as“crowns”) are long established for the capping of glass and, morerecently, plastics bottles. They traditionally consist of a top panellined with a sealing compound, and a peripheral skirt. A corrugation dieprovides fluting along the length of the skirt and the crown is crimpedonto a bottle to close it. The crown is removed with a traditionalbottle opener.

[0003] However, the metal of traditional crowns is relatively thick incomparison with that of other metal closures so that known crowns areinherently costly in material usage. The edge of the crimped and flutedcrown is exposed so that traditional steel crowns are prone to rusting.The raw edge can also cause a safety hazard if the crown is not handledor disposed of correctly.

[0004] According to the present invention, there is provided a metalliccrown closure including a centre panel, and a peripheral skirt portiondepending downwardly therefrom, the distal end of the skirt portionbeing curled outwardly to form a curl portion, the curl portioncomprising at least 180° of material when viewed in cross section andbeing 0.5 to 2 mm in diameter.

[0005] In a preferred embodiment which hides any exposed edge of metalon the crown, the curl portion may comprise around 270° of material.Conventionally, the degree of curl is measured from the point at whichthe side of the skirt portion deviates from being linear. The curl maybe ideally 1.5 mm or less in diameter.

[0006] The invention also provides, in combination, a bottle having aneck which includes an outwardly extending capping bead, and the crownclosure described above, fitted over the neck of the bottle with itsskirt portion around the neck finish and the curl substantiallyunderneath the capping bead such that the outer diameter of the curl ofthe fitted crown is substantially the same as the outer diameter of theskirt portion.

[0007] The Applicant has found that up to 35% thinner gauge material canbe used for the crown closure of the present invention whilst stillachieving the same pressure performance as that of standard flutedcrowns. It is believed that this is due to the build up of metal layersin the curl region. As the curl will, after application of the crownclosure to a bottle, be tucked in under the bottle finish, the thicknessof metal under the bottle finish is two to three times that of the crownside wall and top panel. The double/triple metal thicknesses under thebottle finish enables the crown closure to withstand forces in thisregion during processing or due to carbonated product within the bottle.

[0008] The metallic crown closure is conveniently formed of steel, whichmay be coated with a polymer material. The crown may conveniently beformed of a double reduced steel such as “DR 580”. Double reduced steelis stiffer than the single reduced steel used for conventional crowns.

[0009] Preferably, the double reduced steel of the crown closure is inthe range of 0.1 mm to 0.2 mm gauge, in contrast with 0.235 mm gaugesingle reduced steel which is required for conventional crowns.

[0010] A bottle closed with the crown closure of this invention not onlycreates a distinctive appearance, but the curl portion also serves tomaintain the cut edge of the crown away from the surface of the bottle.Thus, even if rust starts to form on the edge of a steel closure, e.g.in hot and humid climates such as the Far East, this rust is notdeposited on to the bottle surface when the closure is removed.

[0011] The use of alternative materials such as aluminium is alsopossible but probably is not advantageous due to higher raw materialcosts.

[0012] The weight of the crown shell (that is, without any gasketinsert) is typically from 1.3 g to 1.54 g and, when applied to a bottle,the crown is ideally less than 6 mm in height. The formation of a curldoes not require any extra metal from that which is required for theshell of a traditional crown, which ranges from 1.8 g to 2.3 g inweight, typically weighing 2.02 g. The traditional crown is usually 6 mmin overall height after crimping onto the bottle. Ideally the curl issmall in diameter so as to avoid collapse of the curl during applicationto a bottle, but large enough to be able to move radially inwards undera capping bead on the bottle. Furthermore, the crown must be able towithstand pressures which arise when containing pressurised products orwhere pasteurisation is required.

[0013] In one embodiment, the curl may be petaloid in structure with oneor more reformed regions around its circumference which are limited tothe height of the curl itself and do not extend up the plain side wallof the crown. As a result, whether the crown is reformed or not, therelatively plain skirt portion (as opposed to the corrugated skirts usedin conventional crowns) may be used for printing decorative orpromotional material.

[0014] When the crown is applied to a bottle, the curl comprises atleast 180°, although it is preferable that the exposed edge is hiddenfor safety purposes so that the curl is around 270°, and preferably 360°of material when viewed in cross section.

[0015] The crown closure of the invention has significant functionaladvantages. For example, the curled skirt has several advantages overthe conventional corrugated skirt, not least in that it provides less ofa safety hazard if discarded inappropriately. Furthermore, theconventional uncurled and corrugated crown closures are prone to aproblem known as ‘dusting’, in which crowns contact each other duringtransit and the sharp edges of the crowns chip off small particles ofcoating materials, producing dust particles which can causecontamination.

[0016] In addition, contact between conventional crowns can lead todamage to decoration and/or lacquer damage (internal or external) whichis required for protection from corrosion. The curled periphery of thecrowns of the present invention helps to avoid this problem.

[0017] As the crown of the invention is lighter that the traditionalcrown, it is clear that weight savings are made in the packaging ofcrowns for transport.

[0018] According to a further aspect of the invention there is provideda method of capping a bottle with the curled crown of the presentinvention as described above, the method comprising: locating the crownover the neck of a bottle, the neck of the bottle including an outwardlyextending capping bead; and reforming the crown to move at least a partof the curl under the capping bead, thereby securing the crown onto theneck of the bottle.

[0019] The method may further comprise tightening the curled edge of thecrown by distortion from its original shape to, for example, a polygonalshape during capping of the bottle.

[0020] The invention will now be further described by way of exampleonly, with reference to the drawings, in which:

[0021]FIG. 1 is perspective view of a prior art crown closure, appliedto the neck of a bottle;

[0022]FIG. 2 is a side view of a prior art crown closure, applied to theneck of a bottle;

[0023]FIG. 3 is a perspective view of a first embodiment of the crown ofthe present invention, applied to the neck of a bottle;

[0024]FIG. 4 is a perspective view of the embodiment FIG. 3, applied tothe neck of a bottle and reformed;

[0025]FIG. 5 is a schematic sectional view of capping apparatus forcapping a bottle with the crown of the present invention, shown in afirst position;

[0026]FIG. 6 is a schematic sectional view of the apparatus of FIG. 5,shown in a second position;

[0027]FIG. 7 is an enlarged view of a part of FIG. 5;

[0028]FIG. 8 is an enlarged view of a part of FIG. 6;

[0029]FIG. 9 is a schematic sectional view of an alternative apparatusfor capping a bottle;

[0030]FIG. 10 is a perspective view of a capping tool for use in theapparatus of FIG. 9;

[0031]FIG. 11 is a schematic sectional view of the apparatus of FIG. 9,shown in a second position;

[0032]FIG. 12 is a schematic sectional view of an alternative embodimentof the crown;

[0033]FIG. 13 is a schematic sectional view of the crown of FIG. 12,shown after it has been sealed on to a bottle; and

[0034]FIG. 14 is a schematic of different degrees of curl.

[0035]FIGS. 1 and 2 show a prior art crown closure P1, typically of0.235 mm single reduced steel, applied to a bottle and comprising acentre panel P2 and depending skirt P3. The skirt is approximately 6 mmin height and has an exposed lower edge P4. The centre panel istypically 26.5 mm in diameter. A series of alternate ribs P5 and flutesP6 are formed around the whole circumference of the skirt, with the ribsP5 extending over the majority of the height of the skirt P3 so that theskirt has no or at best limited plain surface portions.

[0036]FIGS. 3 and 4 are perspective views of the crown closure 12 of thepresent invention, as applied to a bottle 11, without and with reformingrespectively. The crown can be seen in side section in “apparatus” FIGS.5 to 9 and FIG. 11.

[0037] The crown 12, which is formed from 0.12 to 0.2 mm DR 580 doublereduced steel, typically 0.16 mm gauge, comprises a centre panel 13,typically 26.5 mm in diameter, and a peripheral skirt 14 dependingtherefrom. The skirt 14 is at most 6 mm in height and terminates in anouter curl 15.

[0038] The curled crown of FIGS. 3 and 4 uses a shell of 1.4 g, which issignificantly less weight than the weight of the conventional crown ofFIGS. 1 and 2 (2.02 g). It can therefore be seen that the thinner gaugesused for the curled crown of the present invention present major costsavings. Even the upper end of the gauge range used for the curled crown(i.e. 0.2 mm) is 35% thinner than the 0.235 mm gauge used forconventional crowns. Furthermore, a 0.2 mm curled crown of the presentinvention and a 0.235 mm conventional crown have been demonstrated tohave the same pressure performance when each was applied to a standardglass bottle finish.

[0039] As shown in side section in FIG. 7, for example, the outer curl15 comprises a complete curl including at least 270° of material (seealso FIG. 14). An overcurl of up to 180° may be used to avoid uncurling(exposure of the raw metal edge) during application, although inpractice this has, to date, not been found to be essential. A gasket ofsealing compound 16, typically a polymeric material, is attached to theunderside of the centre panel between the panel and an annular topsurface 17 of the bottle. The bottle also includes an annular cappingbead 18, and the outer curl 15 lies adjacent the capping bead 18.

[0040] A curl diameter of between 0.5 and 1.5 mm is recommended forapplying the curled crown to the bottle where pasteurisation is requiredor where the product to be contained in the bottle is pressurised. Thecurl provides a build up of thicknesses under the bottle finish, therebyallowing thinner gauge materials to be used for the curled crown of thepresent invention. Although the top panel of the crown is subject to thesame forces, the panel can be stiffened by a variety of techniques notavailable around the neck finish, such as by providing a concavity inthe centre panel, embossing etc.

[0041] It can be seen that the crown closure 12 when attached to bottle11 has a distinctive slimline appearance. Furthermore, the edge 19 ofthe closure is hidden so as not to pose a danger to users, and yet it isalso maintained in a position away from the surface of the bottle sothat if rust starts to form on the edge 19, it is not in contact withthe bottle 11.

[0042] The crown of FIG. 4 has a petaloid structure with alternatingreformed and plain areas. Although the crown shown in FIG. 4 hasregularly spaced reformed “petals” around its circumference, thesepetals could vary in number and/or position as desired.

[0043] Whether the skirt has a petaloid or plain structure, bothembodiments shown have significant smooth skirt portions. This makesprinting or other features possible on the skirt which would be lostand/or distorted by the reforming of the conventional crown of FIGS. 1and 2. This is an advantage where the product to be sold will be stackedon supermarket shelves, with the top panel of the crown not visible tothe customer.

[0044] Referring now to FIG. 5, an apparatus for capping a bottle 11with the crown 12 of the present invention is shown generally at 1. Theapparatus 1 comprises a capping tool 2 reciprocal on a central shaft 3.The capping tool is generally cup shaped and comprises a cylindricalside wall 4 depending from an upper end 5. A central hole 6 allows theshaft 3 to pass therethrough. The lower end of the tool is open, theopening 7 being provided with a tapered infeed section 8. The shaft 3has a piston plate 9 at the lower end thereof and a spring 10 isconstrained between the piston plate and the upper end 5 of the tool.

[0045] For capping the bottle 11, the bottle is first presented to theapparatus 1, with the crown closure 12 placed thereon. To attach thecrown 12 to the bottle 11, the piston plate 9 holds the crown inposition, and the capping tool 2 is lowered on the central shaft fromthe position shown in FIGS. 5 and 7 to that shown in FIGS. 6 and 8. Asthe capping tool 2 is lowered, the tapered infeed section 8progressively contacts the outer curl 15, moving it downwardly andinwardly to the position shown in FIG. 8, in which it lies under thecapping bead 18. During this movement the outer curl 15 may be partiallyuncurled, but remains curled to the extent that at least 270° ofmaterial is contained within the curl. When such uncurling has not takenplace, the overcurl could be reduced to zero or near zero withcorresponding cost savings in cut edge.

[0046] FIGS. 9 to 11 show an alternative embodiment of apparatus forapplying the crown of the present invention to a bottle, in whichfeatures similar to those in FIGS. 5 to 8 are designated with likereference numerals. The apparatus is suitable for capping crown closures12 in which the outer curl 15 is provided with substantially more thanone turn of material, in this case approximately 1 ¼ turns (450°) ofmetal. The capping tool 2 differs from that described previously in thatthe tapered infeed section 8 is castellated, and has inwardly extendingsegments 20 separated by land portions 21. This tool is shown in FIG.10.

[0047] The operation of the apparatus is similar to that previouslydescribed, with the capping tool 2 being lowered on the central shaft 3as shown in FIG. 11. Prior to capping, the curl 15 extends out beyondthe diameter of the skirt. The segments 20 contact the outer curl 15 soas to urge it under the capping bead 18 at those positions around itscircumference in which contact is made. The result is the petaloidstructure of FIG. 4, as described above, with the reformed petalslimited to the curl itself. This contrasts with conventional crowns onwhich full height flutes are formed prior to application.

[0048] The segments 20 of the tool as shown in FIG. 10 could be limitedto only part of the circumference of the tool to provide productdifferentiation. Similarly, the number and spacing of the “petals” canbe varied if the customer so requires, simply by changing the crimpingring, which is a low cost item.

[0049] In both of the above embodiments, the crown closure 12 may beremoved from the bottle 11 using a conventional bottle opener. In thearrangement of FIG. 4, the plain areas 23 provide particularly goodsites on which the bottle opener can be employed. Clearly, being a crownclosure, the evidence of a bottle opener on the top panel is anindication that tampering has occurred.

[0050]FIGS. 12 & 13 show an alternative crown closure having a centrepanel 13, peripheral skirt 14 and sealing compound 16 etc. as previouslydescribed. In the closure of FIGS. 12 & 13, however, the skirt 14 isflared outwardly and the curl at the end thereof is an inwardly facingcurl 24. The closure 12 is placed on a bottle 11 as before, andpresented to apparatus as previously described with reference to FIGS. 5to 8. The capping tool moves downwardly reforming the skirt 14 into theposition shown in FIG. 13, in which the inner curl 24 is rolled underthe capping bead 18 on the bottle 11, securing the crown closure on tothe bottle as previously described.

[0051] The schematic of FIG. 14 demonstrates how the curl angle ismeasured and what is meant by an “open” or “closed” curl.

1. A metallic crown closure including a centre panel, and a peripheralskirt portion depending downwardly therefrom, the distal end of theskirt portion being curled outwardly to form a curl portion, the curlportion comprising at least 180° of material when viewed in crosssection and being 0.5 to 2 mm in diameter.
 2. A crown according to claim1, which is formed of steel and, optionally, coated with a polymermaterial.
 3. A crown according to claim 2, which is formed of a doublereduced steel such a s ″DR 580, which is in the range of 0.1 mm to 0.2mm gauge.
 4. A crown according to any one of claims 1 to 3, in which thediameter of the centre panel is of the order of 26.5 mm.
 5. A bottlehaving a neck which includes an outwardly extending capping bead andfitted with the crown of any one of claims 1 to 4, in which the crown isfitted over the neck of the bottle with its skirt portion around theneck finish and the curl substantially underneath the capping bead suchthat the outer diameter of the curl of the fitted crown is substantiallythe same as the outer diameter of the skirt portion.
 6. A bottleaccording to claim 5, in which the crown applied thereto is less than 6mm in height.
 7. A bottle according to claim 5 or claim 6, in which thecurl of the crown applied to the bottle includes one or more reformedregions around its circumference which are limited to the height of thecurl itself and do not extend up the plain side wall of the crown.
 8. Abottle according to any one of claims 5 to 7, in which the curl of thecrown applied to the bottle comprises at least 270° of material whenviewed in cross section.
 9. A method of capping a bottle with the crownof any one of claims 1 to 8, comprising: locating the crown over theneck of a bottle, the neck of the bottle including an outwardlyextending capping bead; and reforming the crown to move at least a partof the curl under the capping bead, thereby securing the crown onto theneck of the bottle.
 10. A method according to claim 9, furthercomprising tightening the curled edge of the crown during capping of thebottle by distortion from its original circular shape to a polygonalshape.